1. Field of the Invention
This invention relates to a room temperature vulcanizable polyorganosiloxane composition. More specifically, this invention relates to a room temperature vulcanizable polyorganosiloxane composition whose cured product will not soil other substrates which have been brought into contact with the composition after the composition has been cured.
2. Background Information
Various room temperature vulcanizable polyorganosiloxane compositions which cure into resins or rubbers are conventionally used as electrical insulating materials, adhesives, coating materials, for sealing containers, and as a sealing material.
In particular, a so-called oxime-liberating room temperature vulcanizable polyorganosiloxane composition, which cures with the production of a ketoxime, is widely used as a single-package curable composition because it can be stored uncured in a sealed container for long periods of time and is rapidly cured by atmospheric moisture upon exposure to the atmosphere while seldom corroding other substrates which are brought into contact with it.
However, the above room temperature vulcanizable polyorganosiloxane composition suffers from the drawback of soiling other substrates which come into contact with the cured product when it is employed in the applications cited above. For example, when the composition is employed as an electrical insulating material, it causes poor contact by neighboring electrical contacts. When it is employed as a coating agent, it hydrophobicizes the underlying substrate. When it is employed as a construction sealing material, it soils the sealing joint and its surrounding areas. When it is employed to seal a container, polyorganosiloxane will elute into the sealed liquid.
Various methods were examined by the present inventors in investigating the causes of the above defects in ketoxime-liberating room temperature vulcanizable polyorganosiloxane compositions with the goal of improving these compositions and this invention was thus developed as a result.